Controlled sol-gel synthesis of oxygen sensing CdO : ZnO hexagonal particles for different annealing temperatures.

CdO : ZnO hexagonal particles were synthesized by a sol-gel precipitation method at different annealing temperatures. A mixed crystal phase of cubic and wurtzite structures was observed from X-ray diffraction patterns. The micrographs showed hexagonal shapes of the CdO : ZnO nanocomposites particles. The energy dispersive X-ray spectroscopy mapping images showed a uniform distribution of the Cd and Zn. The CdO : ZnO nanocomposite pallet annealed at 550 °C has an electrical resistance of 0.366 kΩ at room temperature. The nanocomposites showed an excellent sensing response against oxygen gas with a sensing response of 47% at 200 °C for the CdO : ZnO particles annealed at 550 °C. The sensor response and recovery times were found to be 43s and 45s, respectively. The sensor response was due to the sorption of oxygen ions on the surfaces of the CdO : ZnO hexagonal particles.